In modern textile machinery of the aforedescribed type, especially spinning and twisting frames provided with rows of supply spools, it is known to trigger an automatic spool change by monitoring the degree of filling of a spool.
In a ring-spinning machine, for example, the actual weight and the estimated running time of each individual supply spool is determined and the point in time at which each spool is expected to run out can be established (see German patent document-open application No. DE-OS 32 16 218) and this information used to initiate an automatic replacement of the empty supply spool.
While such systems certainly represent an improvement over the operator's surveillance of the supply of spools and the manual initiation of a spool replacement operation when the operator detects an empty supply spool, they are characterized by high cost for the installation and operation of the monitoring systems because a respective monitoring device must be provided for each spool.